Process for the production of lubricating oils by solvent extraction



United States Patent O PROCESS FOR THE PRODUCTION OF LUBRICAT- ING OILS BY SOLVENT EXTRACTION Edward F. Wadley, Baytown, Tex., assigner, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, NJ., a corporation of Delaware Application August 3, '1955, Serial No. 526,097

4 Claims. (Cl. 208-312) The present invention is directed to the recovery of lubricating oil. More particularly, the invention is directed to the recovery of lubricating oil from cracked fractions. In its more specific aspects, the invention is directed to recovering lubricating oil from cracked petroleum fractions in admixture with extracted fractions from crude petroleum fractions.

The present invention may be briefly described as a method for recovering lubricating oil which comprises contacting a solvent extract containing phenol from the phenol extraction of a crude petroleum lubricating oil fraction boiling above about 900 F. with a cycle stock from iluid catalytic cracking of petroleum hydrocarbons boiling substantially below about 900 F. but diierent from the boiling range of the lubricating oil fraction under conditions to form an extract phase and a rainate phase and then recovering lubricating oil fractions by distilling said raflinate phase.

The lubricating oil fraction from crude petroleum boils above about 900 F. but preferably above about 1015 F. and suitably is a fraction termed in the industry as a bright stock. It has been found that bright stock extracts containing phenol when contacted with a cycle stock from a tluidized catalytic cracking operation the phenol in the bright stock may extract undesirable lubricating oil components from the cycle stock and allow the production of a rainate containing only the desirable lubricating oil components from the cycle stock plus some components from the bright stock; the ready separation of the cycle stock lubricating oil fractions from the bright stock may then be accomplished by distillation.

' The solvent extraction employing the phenol extract of crude petroleum lubricating oil fractions may suitably be `conducted at temperatures in the range from about 170 F. to about 260i F. but preferably at a temperature in the range from about 200 to about 260 F. to recover the material of highest viscosity index from the cycle stock.

The phenol extract is suitably employed in an amount suflicient to provide a suicient amount of phenol to form the rafliniate phase containing the cycle stock lubricating oil components. For example, a suflicient amount may be employed to provide a treat in the rangefrom about 100% to about 200% by volume based on the cycle stock. A phenol treat of approximately 125% by volume based on the cycle stock may be suitable.

As an example of the composition of the phenol extract, it may suitably contain about 89% phenol, about 6% water and about 5% of the solvent extract which may have a gravity of about 15.2 API, a viscosity of about 19,315 sec. at 100 F., a viscosity of about 300 secs. at 210 F. and having a viscosity index of about 20.

The cycle stock employed in the present invention is suitably a heavy gas oil fraction obtained from the fluidized catalytic cracking of petroleum fractions, such as gas oils and the like. In the lluidized catalytic cracking operation, a silica-alumina, a silica-magnesia, or a silicaice zirconia catalyst having particle diameters in the range from about Oto 200 microns is suspended in the vaporized hydrocarbons at a temperature in the range from about 800 to about 1l50 F. to cause the cracking of the vaporized hydrocarbons. The catalyst is: separated from the cracked products and the cracked products subjected to a distillation operation. It is from this distillation operation that the cycle stock is obtained which suitably boils substantially below about 900 F. and which contains lubricating oil components. This fraction may boil in the range from about 670 F. to about 1015 F. and boiling substantially below about 900 F. The cycle stock may be suitably fractionally distilled prior to extraction with the bright stock extract as may be desirable to reduce its end boiling point to about 900 F. These fractions may be suitably recovered in accordance with the present invention.

The present invention will be further illustrated by reference to the drawing in which the single figure is a ow diagram of a preferred mode.

Referring now to the drawing, a bright stock which is suitably a crude petroleum lubricating oil. fraction boiling above about 900 F. and in the range from about 950 F. to about l200 F. is introduced by line 11 into a rst extraction zone 12 whererit is countercurrently contacted containing liquid-liquid internal contacting means, such as bell cap trays and the like, by way of which the phenol and the bright stock are intimately contacted. By ad-A justment of suitable temperatures in extraction zone 12, a

raffinate is formed which is withdrawn therefrom by line 14 for recovery of the lubricating oil components therefrom and the phenol. suitable treatment as may be desired forms desirable lubricating oil components.

The bright stock extract is withdrawn from the extraction zone 12 by line 15 and While still containing phenol is introduced into a second extraction zone 16 which is similar to extraction zone 12. Like extraction zone 12, it Will be understood that extraction zone 16 is equipped with all auxiliary equipment necessary, such as means for inducing reliux, and the like. Introduced into extraction zone 16 by line 17 is a catalytic cracking stock of the type mentioned before which is passed through a preheater 18 in line 17 by way of which the temperature of the cycle stock is raised to about the extraction temperature, which may be in the range from about to about 250 F. In extraction zone 16 the bright stock extract and the cycle stock fraction are contacted countercurrently using a suflicient amount of extract to provide about treat with phenol under temperature conditions of about 200 to 225 F. to form a second ratlinate phase which is withdrawn from zone 16 by line 19 and a second extract phase which is withdrawn from zone 16` by line 20. The second extract phase is discharged into a phenol stripper 21 which is provided with a heating means illustrated by steam coil 22 by way of which phenol is removed from the cycle stock extract, the phenol being recovered from zone 21 by line 23 While the cycle stock extract is discharged from zone 21 by line 24. The cycle stock extract comprises aromatic components which may i like.

The second raffinate phase is discharged by line 19 into a fractional distillation zone 25 provided with a heating means illustrated by steam coil 26 by means of which temperature and pressure conditions are adjusted to remove phenol `from the second rainate, this phenol being This bright stock raffinate after.

recovered by line 27 and' admixed with the phenol from line 23 for re-use in the first extraction zone 12.

Withdrawn from the fractional distillation zone 25 by line 28 is a lubricating oil fraction which suitably may be a 75 neutral oil, by line 29', a second lubricating oil` fraction may be withdrawn which may suitably be a 1'00 or 150 neutral oil, andl by line 30 a light motor oil fraction may be recovered. The bright stock extract is discharged from zone 25 by line 31' for further use or processing as may be desired.

From the foregoing -brief description of the invention, itwill be seen that it is possible to recover lubricating oill components from catalytic cracking cycle stock employing the bright stock extract containing phenol as the solvent.

The invention willv be further illustrated by the following runs in which cycle stock from a uidzedv catalytic crackingv operation was contacted with a solvent extract containing phenol. In one instance, the solvent extract employing the bright stock was contacted with the cycle stock at a temperature ranging from 170 to 180 F. and, in another instance, a temperature ranging from about 210 to 223 F. was employed.

The following table presents the inspections on the raiiinate obtained from extraction with the solvent extract after dewaxing. Also presented are inspection characteristics on fractions obtained by vacuum distillation of the dewaxed oil.

Table l Run 1 Run 2.

Phenol Composition:

Percent Phenol 89. 89. 0 Percent Water 6. 0 6.0 Percent Solvent Extract 1 6.0 5.0 Phenol Treat, Vol. Percent- 125 127 Tower Temperature, F 18o/170 223/210 Ranate, Yield. Percent 6 Gravity, API 32. 5 34. l Vis. at 210 F., SSU... 40.8 41. 6 V.G.C.2 0.812 0.793 Extract, Yield, Percent 42 64 Gravity, API 2.8 10.4 Vis. at 210 F., SS 5l. 45. 8 V.G.C.2 1. 045 0. 975 Dewaxed Raftinate:

Vis. at-

100" F., SSU 171. 177.0 210 F., SSU 44. 5 45.1 Vl 97 101 Pour, F 5 10 Run 1 Run 2 Vacuum Dist. on Dewaxed Oil V/lOO V.I. V/lOO V.I.

SSU SSU 0-10 Fraction 71. 2 87 63.0 98 10-2(l)7 76. 6 89 73. 9 105 20-30. 84. 8 91 8l. 9 105 30-40. 94. 0 91 93. 6 109 40-50. 107. 2 90 112.0 110 50-60. 131. 2 96 137.0 110 60-70. 167.3 98 179. 2 108 7080 249 93 255 102 80-90 454 85 470 93 10% Bottoms 20, 000 50 16, 787 47 From the foregoing data, it will be seen that it is possible to separate lubricating oil fractions of high viscosity index from the dewaxed raiiinate. By operations at a temperature in the range from 170 to 180 F., the ma terial of lower viscosity index is obtained while at approximately 40 higher temperatures higher viscosity in dex materials are separable and recoverable,

The present invention is of considerable advantage, in that by virtue of selecting a solvent extract which boils in a different boiling range than the cycle stock, it is possible to separate and recover valuable lubricating oil components from the solvent extract. In other words, employing the solvent extract, some of the second railinate produced will contain material originally present in the lubricating oil` extract which hasv been displaced to the `second rafiinate phase. The data presentedk in the foregoing table show that part of the lubricating oil sol,- vent extract appears in the second raiiinate phase. From these data, it may be seen that the bottoms fractionobtained when extracting cycle stock with the lubricating oil extract contains materials of 16,000- to 20,000 SSU viscosity at F. These materialsy are rejected from the raiiinate phase by the distillation step of the present invention so that the overhead fraction is composed entirely of the lighter boiling lubricating oil fractions derived from the cycle stock.

In accordance with the present invention it isy desired to employ hydrocarbon fractions boiling above 900 F. and preferably above 1015" F. in the solvent extract in order to obtain the desirable separation.

The nature and objects of the present invention having` been completely described and illustrated, what 1 wish to claim as new and useful and to secure by Letters Patent is:

l. A method for recovering lubricating oil which cornprises contacting a solvent extract containing phenol and lubricating oil components from the phenol' extraction of a crude petroleum lubricating oil fraction boiling above about 900 F. with a cycle stock containing lubricating oil components from fluid catalytic cracking of petroleum hydrocarbons boiling substantially below about 900 F. but different from the boiling range of the crude petroleum lubricating oil fraction under conditions including a temperature in the range from about to about 260 F. and a sufficient amount of said solvent extract to provide a phenol treat in the range from about 100% to about 200% by volume based on the cycle stock to form an extract phase comprising aromatic components originally present in the cycle stock and a rainate phase containing said lubricating oil components from said solvent extract and from said cycle stock, fractionally distilling said rainate phase into a phenol fraction, a high Viscosity index lubricating oil fraction and a fraction containing high viscosity material originally present in the solvent extract, and separately recovering said distilled fractions.

2. A method in accordance with claim l in which the lubricating oil fraction boils above about l0l5 F.

3. A method in accordance with claim 5 in which the cycle stock boils below the boiling range of the lubricating oil fraction.

4. A method for recovering lubricating oil fractions which comprises contacting in a solvent extraction zone a solvent extract containing phenol and lubricating oil components from the phenol extraction of a crude petroleum lubricating oil fraction boiling above about 900" F. with a cycle stock including lubricating oil components from fluid catalytic cracking of petroleum hydrocarbons boiling substantially below about 900 F. but having a lower boiling range than the crude petroleum lubricating oil fraction under conditions including a temperature in the range from about 200 F. to 260 F. to form an extract phase comprising aromatic components originally present in the cycle stock and a raffinate phase containing said lubricating oil components from said solvent extract and from said cycle stock, said solvent extract being employed in an amount sufficient to provide a phenol treat in the range from about 100% to about 200% by volume based on the cycle stock, fractionally distilling said railinate phase into a phenol fraction, a high viscosity index lubricating oil fraction and a tra- Afi-IlluA tion containing high viscosity material originally present in the solvent extract, and separately recovering said distilled fractions.

References Cited in the le of this patent UNITED STATES PATENTS Tijmstra Dec. 6, 1938 Van Dijck May 21, 1940 

1. A METHOD FOR RECOVERING LUBRICATING OIL WHICH COMPRISES CONTACTING A SOLVENT EXTRACT CONTAINING PHENOL AND LUBRICATING OIL COMPONENTS FROM THE PHENOL EXTRACTION OF A CRUDE PETROLEUM LUBRICATING OIL FRACTION BOILING ABOVE ABOUT 900*F. WITH A CYCLE STOCK CONTAINING LUBRICATING OIL COMPONENTS FROM FLUID CATALYTIC CRACKING OF PETROLEUM HYDROCABONS BOILING SUBSTANTIALLY BELOW ABOUT 900*F. BUT DIFFERENT FROM THE BOILING RANGE OF THE CRUDE PETROLEUM LUBRICATING OIL FRACTION UNDER CONDITIONS INCLUDING A TEMPERATURE IN THE RANGE FROM ABOUT 170* TO ABOUT 260*F. AND A SUFFICIENT AMOUNT OF SAID SOLVENT EXTRACT TO PROVIDE A PHENOI TREAT IN THE RANGE FROM ABOUT 100% TO ABOUT 200% BY VOLUME BASED ON THE CYCLE STOCK TO FORM AN EXTRACT PHASE COMPRISING AROMATIC COMPONENTS ORIGINALLY PRESENT IN THE CYCLE STOCK AND A RAFFINATE PHASE CONTAINING SAID LUBRICATING OIL COMPONENTS FROM SAID SOLVENT EXTRACT AND FROM SAID CYCLE STOCK, FRACTIONALLY DISTILLING AND RAFFINATE PHASE INTO A PHENOL FRACTION, A HIGH VISCOSITY INDEX LUBRICATING OIL FRACTION AND A FRACTION CONTAINING HIGH VISCOSITY MATERIAL ORIGINALLY PRESENT IN THE SOLVENT EXTRACT, AND SEPARATELY RECOVERING SAID DISTILLED FRACTIONS. 